In a conventional control technique, an input value approaches a maximum value in the event of a high-load demand, with however performance at a load appearing stagnant instead of increasing at a direct proportion. That is, saturation has reached as the input signal is incapable of providing more energy to the load, such that a surge is caused. A maximum value of the surge wave is often extremely close to a maximum load of a power element, in a way that a power stage becomes constantly exposed to risks of being burned and damaged.
In one conventional technique, a surge signal is mitigated or eliminated using a circuit hardware design, which disposes an extra detection device at a control circuit board. To further ensure the functionality of the device, an additional associated activation power is provided. Thus, not only operation performance of the control device is degraded but also the volume and costs of the control device are increased. Meanwhile, associated configurations of connected sub-systems and components also need to be adjusted, further complicating the overall design. In another conventional technique, specifications of the power element are augmented with increased power volume and size to prevent burning and malfunction of the power stage of the control device. Alternatively, rather than changing the specifications, a filter circuit and a capacitor of higher specifications are additionally provided for filtering and removing harmonic signals accompanying the surge wave. Such method, although capable of lowering possibilities of system malfunction, significantly increases manufacturing costs. In another method, an amplitude of the input signal may be reduced to decrease the amount of the surge wave. However, this method undesirably affects a power output of the load, such that the system is restrained from exercising maximum performance required by specifications and results in a cost waste.